Dynamo-electric machine.



No. 821,064. PATENTED MAY 22, 1906. F. smBR. DYNAMO ELECTRIC MACHINE.

APPLIUATIDN FILED MAY 1,1905.

WITNESSES III mu PIT!!! CO. IASIIIHMOIL nc,

. 2, that are provided with magnetizing-coils 3 Rented in-seii'esfwiththe tli y for the purpose of preventin in" none s arkbetween, theconunutaor-lgars an UNITED STATES PATENT. OFFICE.

F ERDINANDLSIEBER, OF WILKINSBURG:*PENNSYLVANIA, ASSIGNOR TOWESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, ACORPO- RA'HON OF PENNSYLYANIA.

pYNAmo-ELEcTiuo mam-nus.

I No. 821,064.

Specification of Letters Patent.

atentecl May 22, 1906.

Application filed la; 1, 1805. Serial No 268,821.

Dyrmmo-Electric Machines, of which the following is a specification.

M invention relates to dynamo-electric machines, and particularly tothose-in which the speed may be varied by varying the amount ofresistance in circuit with the fieldma finet Windi 1e object i myinvention is to provide ,improved means for enablingv motors of theabove character to o crate at varying speeds and in either directionwithout shifting the commutator-brushes and without injurious arkingbetiveenthe eomrnutator bars and -t e brushes. Y V .1 D

It has heretofore beejzp to provide the; field magnet rain electricmotors with auxiliary polar jars "of relatively sisal! cross-sectionalarea alternate in position'with the main" o ectzons and r at areconwhich are provided wit tyre-winding the brushes when changes in speedare reflected and whenthe direction of rotation is reversed.

y invention is an im rovement over such mama: and it consists n COIIGBHtlQtIIIgfhB con'v utions of the coils of the auxiliar winding asnear thearmature as po'ssible,so t at the winding may serve both as an effectivecompensatlng winding for the field produced by the. ampereturns of thearmature and as an e for commutatmg-poles.

re 1 of the accompanying drawings is a part ally-diagrammatic view, 1nside elevazfifimf a motor constructed in accordance homng a m ificationof the structure I? lt serringto Fig. 1 of the drawi s, the motor 1 isshown as comprising a fi'el -n 1agnet frame 1, having mam polar.pro3ections and an armature 4, the coils of which are connected in theusual manner to the bars of a commutator-cylinder 5 with wh ch brushes.6 engage. The field-m agnet winding-consistt invention and Fig. 2 is asimilar. ,ti'e

ing of the coils 3 is shown as connected in shunt to thearniaturc-winding, and ifit is so connected or if it is excited from anindependent source the amount of current that traverses it may be variedby var ingtthe amount of a resistance 7 that is mclull cdqn circult withit. Although I have illustrated amotor the main field magnet winding ofwhich is of the shunt variety, such illustration is not to be construedas excluding any other known variety of'lieldemagnct winding onwindiugsthe use of which an ay he desired. Secured to the field-magnet frame 1and alternating in position with the polar projections 2 are auxiliarypolar projections S of small cross-sections area as compared with thecross-sectional area of the polar projections 2, coils 9 being placedupon the polar pro'ections 8 and eonnoctcd in series relation wit thearmature-winding. The coils 9 are so formed as to bring the componentconvolutions as near to the armature as possible and to occupy the sraces between projections 'an their coils. The convolutions of the coils9 are concentrated as near the armature as possible in order that theymay serve to compensate portions of the field produced by theampere-turns of the arms.- ture and at the same time serve as cxcitincoils for the polar projections 8 and enable the motor to effect goodcommutation in accordence with princ ples well understood by thoseskilled in the art. I

If, as has been the usual practice, the convolutions of the coils 9'weredistributed along the lengths of the polar projections .8, com-Earatively little compensating effect would tributed along the length ofthe auxiliary.

the main polarpole-pieces, poor speed regulation and a tendarmaturereaction will vary as the amount of armature-current varies and beindependern;

ency to hunting would occur in case the poieof the saturation of thepole-pieces, so that good speed regulation and good commutation may beobtained and all tendency to hunting be avoided under all conditions ofoperation.

Instead of securing the auxiliary polar projections to the field-magnetframe, as shown in Fig. 1, they may be otherwise supported as shown, forexample, in Fig. 2 at 8"without sacrificing the advantages of myinvention; but substantially the structure shown in Fig. 1 willgenerally be found more satisfactory as regards both manufacturing andoperating conditions.

I claim as my invention- 17 In a dynamo-electric machine, thecombination with an armature, of a field-magnet frame provided with mainpolarprojections and with auxiliary polar rejections of smallercross-section that are located between the main olar projections and arerovided with coils t at are concentrated in c ose proximity to thearmature. y a

2. In a dynamo-electric machine; the combination with an armature, of afield-magnet frame provided with main polar projections and withauxiliary olar projections of smaller crosssectio n t at are locatedintermediate the main polar projections and are provided'with coils thatare concentrated in close proximity to the armature and are'connected inseries with the armature-winding.

3. In a dynamo-electric machine, the combination with an armature of afield-ma net frame that is provided with sets of a ternatelydisposedpolar projections havingwindings that are connected respectively inseries and in shunt relation to the armatureposed polar projections ofrespectively 'fi'er ent cross-sectional area and windings there for thatare connected respectively mfseries and in shunt relation to thearmature-winding, the coils of the series-connected winding beingconcentrated near the armature.

5. In a dynamo-electric machine, the combination with an armature, and afield-magnet frame havin a set of main pole-pieces, and a set of auxiiary pole-pieces that alternate in position wit the main pole-pieces, ofa set of coils for the auxiliary polepieces that are concentratedadjacent to the arina ture and constitute a compensating and regulatingwinding. P

6. In a dynamo-electric machine, the combination with an armature, of afield-magnet having a set of main coils and a set of auxiliary coilsthat alternate in position with the main coils and are concentratedadjacent to the armature to constitute a compensating and regulatingwinding.

In testimony whereof I have hereunto subscribed my name this 28th day ofA ril, 1905.

FERDINAND S BER.

Witnesses:

OTTO S. SOHAIRER, BIRNEY Hmias.

